This manual is intended to guide installers in the installation,
commissioning and maintenance of the Grant Boilerhouse Combi oil
boiler. A user guide for the operation of this boiler is attached to the
back of this manual.
1.1 LOW NOX TECHNOLOGY
All Grant oil condensing boilers are based on Low NOx
technology. They are designed to meet both the European eco-
design (ErP) emission limits introduced in September 2018 (<120mg
/ kwh) and to maintain the high yields expected from Grant Vortex
oil boilers. They combine the proven technology of the Grant
condensing boiler with the Cuenod MAX compact Low NOx flame
burner.1.1
1.2 HOW A CONDENSING BOILER
OPERATES
During the combustion process, hydrogen and oxygen combine
to produce heat and water vapour. The water vapour produced
is in the form of superheated steam in the heat exchanger. This
superheated steam contains sensible heat (available heat) and
latent heat (heat locked up in the flue gas). A conventional boiler
cannot recover any of the latent heat and this energy is lost to the
atmosphere through the flue.
The Grant Vortex Boilerhouse Combi boiler contains an extra heat
exchanger which is designed to recover the latent heat normally
lost by a conventional boiler. It does this by cooling the flue gases
to below 90°C, thus extracting more sensible heat and some of the
latent heat. This is achieved by cooling the flue gases to their dew
point (approximately 55°C).
To ensure maximum efficiency, the boiler return temperature should
be 55°C or less, this will enable the latent heat to be condensed out
of the flue gases.
• The boiler will achieve net thermal efficiencies of 100%.
To achieve maximum performance from the Grant Vortex
Boilierhouse Combi boiler, it is recommended that the heating
system is designed so that a temperature differential of 20°C
between the flow and return is maintained.
The Grant Vortex Boilierhouse Combi boiler will however still
operate at extremely high efficiencies even when it is not in
condensing mode and therefore is suitable for fitting to an existing
heating system without alteration to the radiator sizes. The boiler is
capable of a maximum flow temperature of 75°C.
1.3 BOILER DESCRIPTION
Grant Vortex Boilerhouse Combi boilers are designed to be
installed inside the building in a dedicated and ventilated room
called the boiler room.
The Grant Vortex range of automatic pressure jet oil boilers have
been designed for use with a fully pumped central heating system
with indirect domestic hot water cylinder.
They are not suitable for use with either a direct cylinder or a
‘primatic’ cylinder or gravity hot water.
The boilers are suitable for use on open vented or sealed central
heating systems. System models are supplied with the necessary
components factory fitted. Refer to Section 7.
All boilers are supplied with the control panel and burner factory
fitted.
All the models in the current Grant vortex boilerhouse combi
range of boilers are designed to comply with the maximum NOx
emissions* under the Energy-related Products Directive (ErP).
* From the 26th September 2018, the maximum NOx emissions for
all new oil fired boilers (up to and including 400kW for both new
build and replacement boiler installations) is 120mg/kWh.
The boilers are supplied with:
-a separate Cuenod burner ready to be fitted,
-a 3bar valve + auto bleed valve to mount
- user manual - installer and commissioning Grant boiler.
1.4 BOILER COMPONENTS
The boiler is fitted with a flue safety thermostat which automatically
shuts down the boiler if the heat output exceeds a preset
temperature of 90 ° C ± 3 ° C.
1 INTRODUCTION
Introduction
Page 6
